The magic number formula
The magic number annualizes net new ARR and divides it by prior-quarter sales and marketing spend, producing a ratio that benchmarks GTM efficiency.``` Magic Number = (Net New ARR × 4) / Prior Quarter S&M Spend ```
Using the prior quarter's spend reflects the lag between GTM investment and closed revenue. The deal you close this quarter was typically influenced by marketing and sales activity last quarter or earlier. The one-quarter lag is a convention, not a universal law. For businesses with long sales cycles, a two-quarter lag may be more accurate.
Interpreting the thresholds
| Magic number | Conventional interpretation |
|---|---|
| Below 0.5 | Efficiency needs improvement before adding spend |
| 0.5 to 0.75 | Acceptable; invest selectively |
| At or above 0.75 | Strong signal to increase GTM investment |
| Above 1.5 | Exceptional efficiency; common in early traction |
Gross-margin-adjusted variant
The standard formula uses top-line ARR. A more rigorous version adjusts for gross margin.
``` Adjusted Magic Number = (Net New ARR × Gross Margin × 4) / Prior Quarter S&M Spend ```
| Scenario | Standard magic number | Adjusted (70% gross margin) |
|---|---|---|
| $500K net new ARR / $800K prior S&M | 2.50 | 1.75 |
| $200K net new ARR / $600K prior S&M | 1.33 | 0.93 |
What the formula does not capture
The magic number is a backward-looking ratio. It tells you how efficiently your previous spend produced this quarter's ARR, but it does not capture pipeline quality, the segment composition of new ARR, or whether new customers are profitable over their lifetime.
Use it alongside sales efficiency and growth rate. A high magic number at a very low base can reflect timing anomalies rather than structural efficiency.
For the broader efficiency context, see magic number and rule of 40.
Frequently Asked Questions
What is the magic number formula?
The magic number equals net new ARR for the current quarter multiplied by four, divided by total sales and marketing spend from the prior quarter. Multiplying by four annualizes the quarterly ARR figure. The prior-quarter spend is used because that investment is what produced the current quarter's pipeline and closed revenue.
What does a magic number above 0.75 mean?
A magic number at or above 0.75 is generally interpreted as a signal that it is efficient to increase sales and marketing investment. Below 0.5 suggests you should focus on improving unit economics before adding spend. Between 0.5 and 0.75 is a zone where efficiency is acceptable but incremental investment should be carefully evaluated.
Should the magic number use gross or gross-margin-adjusted ARR?
The gross-margin-adjusted variant is more accurate. Dividing gross-margin-adjusted new ARR by GTM spend reflects the actual economics of acquiring recurring revenue, accounting for the cost to serve. High-margin businesses will look more efficient under this adjustment; low-margin ones will look less so. Most investor benchmarks use the unadjusted version, so be explicit about which you are using.
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